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Lipophilic Malassezia yeasts are an important part of the human resident skin flora, especially in seborrheic areas. Besides mutualistic interactions with the host they are also linked to diseases although the specific causes are not yet comprehensively understood. The amount of available lipids on the skin correlates with the Malassezia density and also with the occurrence of certain diseases like tinea versicolor. Here, the naturally produced lipids of the sebaceous glands play a role. Hardly studied thus far is the impact of topically applied lipids. Here, growth promotion as well as inhibition of Malassezia cells as well as the production of new metabolites through ester cleavage are possible. One example is the release of antimicrobial fatty acids from hydroxypropyl caprylate through the action of Malassezia lipases. This "self-kill" principle results in the reduction of the amount of Malassezia cells and can be applied as new therapy option for dandruff treatment. A better understanding of the interaction between topica and Malassezia would increase their skin tolerance and open new therapy options., (© 2021. Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

In a preschool a long-lasting outbreak of Trichophyton (T.) tonsurans tinea capitis was stopped by a concurrent screening of all persons at-risk (N = 264) with the hairbrush technique and a therapy based on clinical picture as well as on the quantitative results of the culture. In addition to the 5 symptomatic patients 10 asymptomatic carriers undetected until now were especially important as vectors. With the rising incidence of T. tonsurans and T. violaceum and the return of Microsporum (M.) audouinii in central Europe such outbreaks are likely to occur more frequently. According to the literature an early and comprehensive screening of the entire at-risk population, a combined antimycotic therapy of the symptomatic and at least a topical therapy of the asymptomatic as well as measures of decontamination are important conditions for successful outbreak management. In our hands the hairbrush technique is a reliable, painless and easy-to-perform screening method which also allows a quantification of fungal load.

Sources of infection for Trichophyton (T.) mentagrophytes-a zoophilic dermatophyte-comprise pet rodents (guinea pigs, mice, rabbits) and sometimes cats. Human infections due to dermatophytes after contact with zoo animals, however, are extreme rare. Four zoo keepers from Basel Zoo were diagnosed to suffer from tinea manus and tinea corporis due to T. mentagrophytes. The 22-year-old daughter of one zoo keeper was also infected with tinea corporis after having worked in the snow leopard section for one day. The strain of the index patient was confirmed by a direct uniplex-PCR-EIA and sequence analysis of the ribosomal internal transcribed spacer (ITS) region (18S rRNA, ITS1, 5.8S rRNA, ITS2, 28S rRNA) as T. mentagrophytes. Three young snow leopards from Basel Zoo were identified as the origin of the fungal skin infection. The transmission occurred due to direct contact of the zoo keepers with the young snow leopards when removing hedgehog ticks (Ixodes hexagonus). Two adult snow leopards had developed focal alopecia of the facial region which was diagnosed as dermatomycoses due to T. mentagrophytes by the zoo veterinarians. By sequence analysis, both the strains from the animals and a single strain of the index patient showed 100% accordance proving transmission of T. mentagrophytes from animals to the zoo keepers. Molecular biological identification revealed a strong relationship to a strain of T. mentagrophytes from European mink (Mustela lutreola) from Finland. Treatment of patients was started using topical ointment with azole antifungals, and oral terbinafine 250 mg once daily for 4 weeks. Both adult snow leopards and the asymptomatic young animals were treated with oral itraconazole.

Currently, a mycid is defined as hyperergic reaction that develops from a remote localized infection and in which no fungus is detectable. Criteria for a mycid caused by a dermatophyte (dermatophytid) are (1) proven dermatophytosis elsewhere, (2) no evidence for fungal elements in the lesions of the -id reaction, (3) initially often worsening of the lesions under therapy with highly potent systemic antimycotics, and (4) clearing after the dermatophytosis has been treated sufficiently. The most common dermatophytid is a symmetrical dyshidrotic mycid of the hands in connection with an often highly inflammatory mycotic infection of the feet especially by Trichophyton mentagrophytes. In addition to lichen trichophyticus, dermatophytids associated with tinea capitis may show high clinical variability. They often occur under systemic antimycotic therapy and have to be differentiated from drug reactions. In addition to systemic antimycotic therapy and, if necessary, a short-term application of oral glucocorticoidsteroids, a topical combination of an antifungal and a glucocorticosteroid is effective. It leads to an immediate reduction of inflammation and pruritus, especially if initiation of systemic antifungal therapy has resulted in a flare-up reaction (overtreatment phenomenon).

Because of high exposure (e. g. swimmers and athletes competing on mats) and disposition (e. g. microtraumata of the skin in runners) athletes are prone to a higher risk for mycotic infections by dermatophytes. In disciplines with close contact during competition-especially wrestlers and judoists-infections by the anthropophilic Trichophyton (T.) tonsurans are most important (tinea gladiatorum). These infections are highly contagious and often cause small epidemics especially if the primary source of infection is not promptly recognized. The environment of the athletes (e. g. mats) and asymptomatic carriers may be sources of further spread. Tinea pedis with its clinical manifestations seems to be often underdiagnosed and insufficiently treated. Environmental contamination by fungal spores may be responsible for the significantly higher level of mycotic infections of the feet in children and adolescents active in sports. There is a higher risk for spread of the infection to the toe nails (onychomycosis) and for consecutive infections by bacteria (e. g. erysipelas). More rarely infections by zoophilic or geophilic dermatophytes are seen in athletes (e.g. equestrians). Education and more intensive measures of prevention and environmental decontamination are essential for all dermatophytoses associated with sports.

Based on the technical information that oral terbinafine must be used with caution in patients with pre-existing psoriasis or lupus erythematosus, the literature was summarized. Terbinafine belongs to the drugs able to induce subcutaneous lupus erythematosus (SCLE)-with a relatively high risk. The clinical picture of terbinafine-induced SCLE may be highly variable and can also include erythema exsudativum multiforme-like or bullous lesions. Thus, differentiation of terbinafine-induced Stevens-Johnson syndrome or toxic epidermal necrolysis may be difficult. Therefore, terbinafine should be prescribed with caution in patients who show light sensitivity, arthralgias, positive antinuclear antibodies or have a history of SLE or SCLE. Case reports include wide-spread, but mostly nonlife-threatening courses, which did not require systemic therapy with steroids or antimalarials in every case. Terbinafine is also able to induce or to aggravate psoriasis. The latency period seems to be rather short (<4 weeks). Terbinafine therefore is not first choice if a systemic therapy with antimycotics is indicated in a patient with psoriasis or psoriatic diathesis. Azole derivatives according to the guidelines may be used as an alternative.

Treating eczema with fungal and/or bacterial superinfections or superficial mycoses are a common problem in daily practice. A fungal superinfection as a consequence of a diminished skin barrier might complicate the course of eczema. In addition, in an inflammatory superficial mycotic infection a delayed-type hypersensitivity reaction may result in healing of the lesion, but might also be responsible for irreversible damage of epidermal structures. An example is permanent hair loss by scarring alopecia in the context of inflammatory tinea capitis. In both cases, combination of an antifungal and a glucocorticoid is appropriate in therapy, preferentially in topical application. The use of azole antimycotics is especially helpful, as they are also effective against gram-positive bacteria.

The ability of recognizing various clinical manifestations of mucocutaneous mycosis, making a diagnosis, and establishing a treatment is part of a dermatologist's daily routine. However, due to the fact that clinical manifestations, laboratory diagnostics, and treatment are performed in one hand, laboratory findings are properly classified and interpreted. Since new binding guidelines of the German Medical Association on quality assurance measures in medical laboratory testing came into force, there is much concern among dermatologists of how to comply with these new regulations. It is the intention of the authors to help our readers to implement these new rules in order to make sure that mycological diagnostics continue to be part of a dermatologist's professional work.

Besides dermatophytoses, a broad range of cutaneous infections due to yeasts and moulds may occur in subtropical and tropical countries where they can affect travellers. Not to be forgotten are endemic occurring dimorphic or biphasic fungi in countries with hot climate, which cause systemic and secondary cutaneous infections in immunosuppressed and immunocompetent people. In the tropics, the prevalence of pityriasis versicolor, caused by the lipophilic yeast Malassezia spp., is about 30-40 %, in distinct areas even 50 %. Increased hyperhidrosis under tropical conditions and simultaneously humidity congestion have to be considered as significant disposing factors for pityriasis versicolor. In tropical countries, therefore, an exacerbation of a preexisting pityriasis versicolor in travellers is not rare. Today, mostly genital yeast infections due to the new species Candida africana can be found worldwide. Due to migration from Africa this yeast pathogen has reached Germany and Europe. Eumycetomas due to mould fungi are rarely diagnosed in Europe. These deep cutaneous mould infections are only found in immigrants from African countries. The therapy of eumycetoma is protracted and often not successful. Cutaneous cryptococcoses due to the yeast species Cryptococcus neoformans and Cryptococcus gattii occur worldwide; however, they are found more frequently in the tropics. Immunosuppressed patients, especially those with HIV/AIDS, are affected by cryptococcoses. Furthermore, Cryptococcus gattii also causes infections in immunocompetent hosts in Central Africa, Australia, California, and Central America.Rarely found are infections due to dimorphic fungi after travel to countries where these fungal pathogens are endemic. In individual cases, cutaneous or lymphogenic transferred sporotrichosis due to Sporothrix schenkii can occur. Furthermore, scarcely known is secondary cutaneous coccidioidomycosis due to Coccidioides immitis after travelling to desert-like endemic regions in southwestern states of the United States and in Latin America, where primary respiratory infection due to this biphasic fungus can be acquired. The antifungal agent itraconazole is the treatment of choice for sporotrichosis and coccidioidomycosis. Talaromyces marneffei-until recently known as Penicillium marneffei-is only found in Southeastern Asia. Mycosis due to this dimorphic fungus has to be considered as an AIDS-defining opportunistic infection. After hematogeneous spread, Talaromyces marneffei affects the skin and mucous membranes of the mouth. Amphotericin B and itraconazole can be used for therapy.

Today, tropical and travel-related dermatomycoses must be increasingly anticipated to present in dermatological offices and clinics. Skin infections due to dermatophytes or other fungi may occur after a journey in countries with a high prevalence for the respective causative fungal pathogen, e.g., tinea corporis due to Trichophyton soudanense. Otherwise, more frequently, single infections and even localized outbreaks due to "exotic" or "imported" pathogens of dermatophytoses occur. These epidemics are observed in childcare facilities in Germany and in other European countries. Source of infection are immigrants from Africa and sometimes from Asian countries. Furthermore, African children, and sometimes also adults, are often only asymptomatic carriers of such anthropophilic dermatophytes. Outbreaks of dermatophyte infections with one and more affected children and also adult staff and teachers due to Trichophyton violaceum or Microsporum audouinii in kindergartens and schools are not a rarity these days. Further tropical and travel-associated dermatophytes are Trichophyton tonsurans, Trichophyton schoenleinii, and Trichophyton concentricum. Tinea capitis should be treated in a species-specific manner. Griseofulvin is the treatment of choice for infections due to Microsporum species. In contrast, tinea capitis due to Trichophyton species has to be treated by terbinafine, however, because the agent is not approved for children in Germany, only after receiving written consent of parents. Alternatives are fluconazole and itraconazole. Onset and aggravation of tinea pedis during travel has its origin in a preexisting neglected fungal infection of the feet. In the tropics, exacerbations and secondary bacterial complications of tinea pedis develop under distinctly promoting conditions.

The lipophilic yeast fungus Malassezia (M.) spp. is the only fungal genus or species which is part of the physiological human microbiome. Today, at least 14 different Malassezia species are known; most of them can only be identified using molecular biological techniques. As a facultative pathogenic microorganism, Malassezia represents the causative agent both of superficial cutaneous infections and of blood stream infections. Pityriasis versicolor is the probably most frequent infection caused by Malassezia. Less common, Malassezia folliculitis occurs. There is only an episodic report on Malassezia-induced onychomycosis. Seborrhoeic dermatitis represents a Malassezia-associated inflammatory dermatosis. In addition, Malassezia allergenes should be considered as the trigger of "Head-Neck"-type atopic dermatitis. Ketoconazole possesses the strongest in vitro activity against Malassezia, and represents the treatment of choice for topical therapy of pityriasis versicolor. Alternatives include other azole antifungals but also the allylamine terbinafine and the hydroxypyridone antifungal agent ciclopirox olamine. "Antiseborrhoeic" agents, e.g. zinc pyrithione, selenium disulfide, and salicylic acid, are also effective in pityriasis versicolor. The drug of choice for oral treatment of pityriasis versicolor is itraconazole; an effective alternative represents fluconazole. Seborrhoeic dermatitis is best treated with topical medication, including topical corticosteroids and antifungal agents like ketoconazole or sertaconazole. Calcineurin inhibitors, e.g. pimecrolimus and tacrolimus, are reliable in seborrhoeic dermatitis, however are used off-label.

A patient presented with Majocchi granuloma caused by T. rubrum. By the use of optical brighteners, fungal elements in the deep dermis could be detected more sensitive than with PAS staining. Healing was achieved by long-term use of oral terbinafine (250 mg per day 12 weeks, followed by 250 mg once per week for another 12 weeks).

Case Report: A 12-year-old with a functional circulatory disturbance had toe nail onychomycosis caused by Trichophyton rubrum. There were no other underlying diseases., Therapy and Outcome: Oral therapy with terbinafine 125 mg once weekly in addition to ciclopirox nail lacquer was ineffective. Two years later the disease worsened and A. versicolor was found in pure culture. A preparation of 10% terbinafine HCl in a 20% urea ointment (Onychomal®) applied daily for 4 weeks, then once weekly resulted in complete cure after 7 months.

Background: A dark colored pigmentation of nails can be due to a subungual malignant melanoma. There are, however, many other benign causes and this differentiation is an important challenge in dermatological practice., Problem: When should nail pigmentation be clarified by histological investigations?, Material and Methods: This article gives a survey of the literature on this topic and a review of own experiences with clinical case examples. The various causes of melanonychia are presented and criteria for the early recognition of melanoma of the nail matrix are formulated., Results: The width and depth of color of longitudinal melanonychia do not allow any conclusions on the dignity. If the nail striation is proximally broader than distally, this is evidence of a proliferative event. Confirmation of a subungual hemorrhage does not exclude a malignancy per se. Also detection of pigmentation due to fungi does not exclude the additional presence of a subungual melanoma. A systematic clinical analysis using clear criteria leads to a working diagnosis and suitable treatment., Conclusion: An early and correct designation of nail pigmentation can avoid unnecessary nail interventions but can also be life saving.

Pityriasis versicolor (PV) is one of the most common infectious skin diseases, as well as the most common dermatosis associated with pigmentation alterations of the skin. PV is prevalent in 1% of the population living in temperate climate zones and more common during the summer. In tropical areas, PV is found in up to 50% of all patients consulting a dermatologist. Of the known Malassezia species, M. globosa is currently felt to play a key role in the pathogenesis of PV, as it is most commonly found in PV lesions. In addition, its round-shaped cells may contribute to the characteristic histology of the disease ("spaghetti and meatballs"). However, the clinical appearance of PV including hyper- and hypopigmentation, fluorescence of the lesions, as well as a lack of inflammation despite high fungal load cannot fully be explained by the presence of M. globosa, which is also found on healthy skin. In M. furfur a tryptophan-dependent metabolic pathway generates a number of indole pigments, which may be associated with the clinical appearance of PV. In the model organism Ustilago maydis it was shown that the formation of the indole compounds occurs spontaneously after initial conversion of tryptophan into indole pyruvate controlled by the key enzyme aminotransferase Tam 1. We review the present knowledge of PV and highlight the potential role of Tam1 in explaining the poorly understood aspects of the disease. Promising therapeutic results using the application of Tam1 inhibitors to treat PV support the enzyme's important role in the disease pathogenesis.

Mycobacterium marinum belongs to the non-tuberculous or "atypical" mycobacteria. The reservoirs for these ubiquitous and slowly growing bacteria are both fresh water and salt water. In particular, aquaria should be considered as important source of hobby-related infections especially of fingers, hands and forearms. Affected are both immunosuppressed patients and persons with an intact immune system. Distinctive are erythematous plaques and nodules with tendency for hyperkeratosis, crusting, and superficial ulcerations, sometimes as sporotrichoid lymphocutaneous infection. The histology shows non-caseation granulomas containing epithelioid cells and Langhans giant cells. Using the Ziehl Neelsen staining, typical acid-fast rods are not always detectable. The molecular biological detection of mycobacterial DNA using polymerase chain reaction represents the standard method of diagnosis. Cryotherapy is frequently used as first treatment. For the often long-term tuberculostatic therapy, rifampicin, ethambutol, and clarithromycin are the most used agents.

Adult-onset Still's disease is a rare disorder of unknown etiology. We report the case of a 39-year-old patient who showed the characteristic symptoms: recurrent attacks of fever, arthralgia, maculopapular rash, sore throat, and lymphadenopathy. After the possibility of an infectious or paraneoplastic process was excluded and the laboratory findings were evaluated (increased C-reactive protein, liver values, and ferritin level), the diagnosis was established according to the criteria of Yamaguchi. Therapy with steroids and nonsteroidal anti-inflammatory drugs was started successfully.

Yeasts of the genus Malassezia belong to the normal microflora of the human skin. In addition they are known to cause a variety of skin diseases; the most frequent of which is pityriasis versicolor. Malassezia yeasts are also thought to be associated with seborrheic dermatitis, dandruff and Malassezia folliculitis. Recently the significance of Malassezia yeasts as a trigger factor for atopic dermatitis of the head and neck region has been pointed out. The role of the Malassezia yeasts in these different diseases has been controversial in the past and remains an issue because of difficulties in isolation, culture and differentiation of the organism. Thanks to molecular techniques, 10 species can actually be differentiated. The article presents the different Malassezia-associated diseases, their clinical picture, diagnosis and appropriate therapy. In addition the speciation of Malassezia is reviewed.

Mycotic infections of the anogenital region are very common in dermatological practice. While dermatophyte infections are more frequent in men, genital candidosis is a more striking problem in women. The increasing prevalence of non-albicans species (esp. C. glabrata, C. krusei, C. guilliermondii) with their resistance against azole derivatives may be responsible for therapeutic failures and a relapsing course in some instances. Most superficial infections of the anogenital area respond satisfactorily to topical antifungal treatment, especially if provocative factors and the possibility of sexual transmission are considered. Systemic treatment is recommended in cases of widespread dermatophyte infections, candidosis or systemic mycosis.

The World Wide Web offers an enormous variety of information about medical mycology. To go through the "fungal jungle" and find the website containing the information that is needed requires a great deal of effort and a lot of time. This article provides help in finding information about medical mycology and describes the contents of preselected websites in German and English. These pages address physicians, scientists, and students interested in dermato-mycology. Most of the pages also contain information about mycoses relevant to other medical specialties.

Localized skin infections caused by the pigmented fungi of the genus Alternaria are being increasingly observed. In the past, primarily patients receiving long-term glucocorticoid therapy were likely to have this mycosis, which is commonly traumatic, but now it is frequently encountered in organ transplantation patients. Possible therapeutic options and differential diagnosis are discussed by means of two case reports--a female renal transplant patient infected by A. alternata and a patient with iatrogenic Cushing syndrome infected by A. infectoria. Histopathological differentiation from other fungal infections may be difficult but is of therapeutic and prognostic significance. Finding short hyphae in tissue sections is an important clue. Since A. infectoria shows little conidial growth in culture, rDNA ITS sequencing offers another diagnostic possibility. Therapy has not yet been standardized. Along with surgical intervention, systemic itraconazole is the usual choice.

A 54-year-old recreational angler was stung in his right forefinger by Echiichthys draco. Within a few seconds he developed severe swelling with extreme pain sensation at the sting site, accompanied by dizziness and chill. Even under morphine therapy the pain symptoms were only slightly reduced. During the subsequent weeks, an erythema with marginate medium-sized scaling developed at the sting site and the patient experienced a approximately 50% reduced bending capacity of the forefinger and permanent numbness in this region. After 4 months, Raynaud phenomenon developed limited to the right forefinger. Great weever fishes (Echiichthys spp.) are the most venomous fishes in European waters. In humans, life-threatening sting reactions occur only in exceptional cases. As a commercial antiserum is not available, the therapy is mainly empiric (General measures of first aid and emergency medicine, the wound should be thoroughly washed). Patients should be informed that reduced motion ability, swelling or Raynaud's phenomenon can persist for several months.

Based on molecular data, the genus Trichosporon was recently reclassified. Six human pathogenic species, which are closely related to specific types of infections can be differentiated. By means of commercial test systems and simple key criteria according to Gueho et al. [15], 44 isolates that had been identified as Tr. cutaneum between 7/92 and 1/96, were reclassified. The evaluation of clinical data also included 66 isolates that had not been preserved, and 27 strains of Tr. inkin. Trichosporon species were found in 4.8% of all yeast isolates (3.8% Tr. cutaneum, 1% Tr. inkin). Nearly every other isolate of Tr. cutaneum was cultivated from nail material, while Tr. inkin was mainly isolated from skin in the anogenital region. In 38 cases, reclassification revealed Tr. mucoides; Tr. ovoides and Tr. asteroides were identified in 3 cases each, while Tr. asahii, an especially remarkable pathogen in systemic mycoses, was not found. Clinically, isolates of Tr. mucoides were predominant in toenail mycoses which might be considered in the therapy of onychomycosis. Furthermore, isolates from the skin should be evaluated with respect to the increasing incidence of systemic Trichopsoron mycoses.

Mycobacterium gordonae is an atypical mycobacterium of very low pathogenic potential. It is widely distributed in soil and water and often detected on the mucous membranes of healthy persons. In recent years, there have been numerous reports of infections by M. gordonae in immunocompromised patients. In contrast, only four cases of skin infections by M. gordonae in immunocompetent patients have been published. We report on another patient without evidence of immunodeficiency who developed an atypical mycobacteriosis after a thorn injury during gardening. M. gordonae was isolated by tissue culture. The skin lesion cleared completely after treatment with doxycycline for three months.

Despite the availability of modern antimycotics, which produce high cure rates in early infections, the therapy of advanced chromoblastomycosis is still unsatisfactory. An initial chromoblastomycosis caused by a hitherto unidentified species of the genus Phialophora was diagnosed in a 46-year-old teacher. The organism was isolated twice at an interval of 6 weeks from a partly psoriasiform, partly verrucous lesion on the 4th toe. The infection was apparently acquired 4 years ago during a holiday at Cape Verde. Treatment with itraconazole (Sempera). 200 mg/day, and amphotericin B (Ampho-Moronal) cream for 6 weeks initially resulted in rapid regression. However, 4 weeks after cessation of therapy, the Phialophora species was cultured again from skin scrapings. Complete healing was achieved after re-treatment with itraconazole for 20 weeks at the same dosage in combination with topical amorolfine and local hyperthermia. Until now, no relapse has occurred. The present case demonstrates that this rare disease, which mainly occurs as a traumatic mycosis in the rural population of tropical regions, must be included in the differential diagnosis of psoriasiform or verrucous skin lesions and also included in the list of diseases which may be acquired while on vacation in exotic locations.

A 1-year follow-up in a 12 year old girl suffering from Fox-Fordyce disease is reported. Reddish papules were found in the typical locations in the regions with a high density of apocrine glands. A biopsy specimen showed keratin plugs in the infundibula of apocrine glands. Since hormone therapy could not yet be given, external therapy only was performed, with good results.

The 2-year spontaneous course of a case of cutis marmorata teleangiectatica congenita in a girl is reported. The child had typical cutis marmorata, with teleangiectasis, phlebectasias and ulceration particularly on parts of the left leg and in the anogenital region, with no further anomalies. During symptomatic therapy over 2 years the lesions faded spontaneously.